From: Sven Peter Date: Sun, 14 Dec 2025 11:51:34 +0000 (+0000) Subject: soc: apple: Add hardware tunable support X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a722de305eacb382a5d306f9f8e502f81bab682d;p=thirdparty%2Flinux.git soc: apple: Add hardware tunable support Various hardware, like the Type-C PHY or the Thunderbolt/USB4 NHI, present on Apple SoCs need machine-specific tunables passed from our bootloader m1n1 to the device tree. Add generic helpers so that we don't have to duplicate this across multiple drivers. Reviewed-by: Alyssa Rosenzweig Reviewed-by: Neal Gompa Reviewed-by: Janne Grunau Signed-off-by: Sven Peter Link: https://patch.msgid.link/20251214-b4-atcphy-v3-1-ba82b20e9459@kernel.org Signed-off-by: Vinod Koul --- diff --git a/drivers/soc/apple/Kconfig b/drivers/soc/apple/Kconfig index ad67368892311..d0ff32182a2b4 100644 --- a/drivers/soc/apple/Kconfig +++ b/drivers/soc/apple/Kconfig @@ -38,6 +38,10 @@ config APPLE_SART Say 'y' here if you have an Apple SoC. +config APPLE_TUNABLE + tristate + depends on ARCH_APPLE || COMPILE_TEST + endmenu endif diff --git a/drivers/soc/apple/Makefile b/drivers/soc/apple/Makefile index 4d9ab8f3037b7..0b85ab61aefe1 100644 --- a/drivers/soc/apple/Makefile +++ b/drivers/soc/apple/Makefile @@ -8,3 +8,6 @@ apple-rtkit-y = rtkit.o rtkit-crashlog.o obj-$(CONFIG_APPLE_SART) += apple-sart.o apple-sart-y = sart.o + +obj-$(CONFIG_APPLE_TUNABLE) += apple-tunable.o +apple-tunable-y = tunable.o diff --git a/drivers/soc/apple/tunable.c b/drivers/soc/apple/tunable.c new file mode 100644 index 0000000000000..6593238391715 --- /dev/null +++ b/drivers/soc/apple/tunable.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Apple Silicon hardware tunable support + * + * Each tunable is a list with each entry containing a offset into the MMIO + * region, a mask of bits to be cleared and a set of bits to be set. These + * tunables are passed along by the previous boot stages and vary from device + * to device such that they cannot be hardcoded in the individual drivers. + * + * Copyright (C) The Asahi Linux Contributors + */ + +#include +#include +#include +#include +#include + +struct apple_tunable *devm_apple_tunable_parse(struct device *dev, + struct device_node *np, + const char *name, + struct resource *res) +{ + struct apple_tunable *tunable; + struct property *prop; + const __be32 *p; + size_t sz; + int i; + + if (resource_size(res) < 4) + return ERR_PTR(-EINVAL); + + prop = of_find_property(np, name, NULL); + if (!prop) + return ERR_PTR(-ENOENT); + + if (prop->length % (3 * sizeof(u32))) + return ERR_PTR(-EINVAL); + sz = prop->length / (3 * sizeof(u32)); + + tunable = devm_kzalloc(dev, struct_size(tunable, values, sz), GFP_KERNEL); + if (!tunable) + return ERR_PTR(-ENOMEM); + tunable->sz = sz; + + for (i = 0, p = NULL; i < tunable->sz; ++i) { + p = of_prop_next_u32(prop, p, &tunable->values[i].offset); + p = of_prop_next_u32(prop, p, &tunable->values[i].mask); + p = of_prop_next_u32(prop, p, &tunable->values[i].value); + + /* Sanity checks to catch bugs in our bootloader */ + if (tunable->values[i].offset % 4) + return ERR_PTR(-EINVAL); + if (tunable->values[i].offset > (resource_size(res) - 4)) + return ERR_PTR(-EINVAL); + } + + return tunable; +} +EXPORT_SYMBOL(devm_apple_tunable_parse); + +void apple_tunable_apply(void __iomem *regs, struct apple_tunable *tunable) +{ + size_t i; + + for (i = 0; i < tunable->sz; ++i) { + u32 val, old_val; + + old_val = readl(regs + tunable->values[i].offset); + val = old_val & ~tunable->values[i].mask; + val |= tunable->values[i].value; + if (val != old_val) + writel(val, regs + tunable->values[i].offset); + } +} +EXPORT_SYMBOL(apple_tunable_apply); + +MODULE_LICENSE("Dual MIT/GPL"); +MODULE_AUTHOR("Sven Peter "); +MODULE_DESCRIPTION("Apple Silicon hardware tunable support"); diff --git a/include/linux/soc/apple/tunable.h b/include/linux/soc/apple/tunable.h new file mode 100644 index 0000000000000..531ca814cd023 --- /dev/null +++ b/include/linux/soc/apple/tunable.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0-only OR MIT */ +/* + * Apple Silicon hardware tunable support + * + * Each tunable is a list with each entry containing a offset into the MMIO + * region, a mask of bits to be cleared and a set of bits to be set. These + * tunables are passed along by the previous boot stages and vary from device + * to device such that they cannot be hardcoded in the individual drivers. + * + * Copyright (C) The Asahi Linux Contributors + */ + +#ifndef _LINUX_SOC_APPLE_TUNABLE_H_ +#define _LINUX_SOC_APPLE_TUNABLE_H_ + +#include +#include + +/** + * Struct to store an Apple Silicon hardware tunable. + * + * Each tunable is a list with each entry containing a offset into the MMIO + * region, a mask of bits to be cleared and a set of bits to be set. These + * tunables are passed along by the previous boot stages and vary from device + * to device such that they cannot be hardcoded in the individual drivers. + * + * @param sz Number of [offset, mask, value] tuples stored in values. + * @param values [offset, mask, value] array. + */ +struct apple_tunable { + size_t sz; + struct { + u32 offset; + u32 mask; + u32 value; + } values[] __counted_by(sz); +}; + +/** + * Parse an array of hardware tunables from the device tree. + * + * @dev: Device node used for devm_kzalloc internally. + * @np: Device node which contains the tunable array. + * @name: Name of the device tree property which contains the tunables. + * @res: Resource to which the tunables will be applied, used for bound checking + * + * @return: devres allocated struct on success or PTR_ERR on failure. + */ +struct apple_tunable *devm_apple_tunable_parse(struct device *dev, + struct device_node *np, + const char *name, + struct resource *res); + +/** + * Apply a previously loaded hardware tunable. + * + * @param regs: MMIO to which the tunable will be applied. + * @param tunable: Pointer to the tunable. + */ +void apple_tunable_apply(void __iomem *regs, struct apple_tunable *tunable); + +#endif